PLEASE NOTE: This article is obsolete or related to a discontinued product.

Termnetd a simple Ethernet to Serial daemon

With this daemon is possible to map a TCP/IP port on the FOX Board with one of the available serial port. This is very useful to reach through LAN or Internet old devices that have only serial ports available

Termnetd ( is a GPL program written by Joe Croft that links a socket session to a generic serial port.

In a few words, once configured and launched this daemon, it is possible to connect a socket client (like Telnet or a VB Winsocket OCX) to the FOX Board by TCP/IP and associate the data flow with one of the available serial ports.

In the figure is shown an example where has been linked serial port /dev/ttyUSB0 to the TCP/IP port 7000 and the serial port /dev/ttyUSB1 to the TCP/IP port 7001.

Ethernet to serial link using Termnetd

The association between the TCP/IP ports and the related serial port can be configured in the file /etc/termnetd.conf that is a simple text file like this:.

7000:on:/dev/ttyUSB0:B57600 CLOCAL CS8;
7001:on:/dev/ttyUSB1:B57600 CLOCAL CS8;

To launch in execution termnetd the command is:


For other information on termnetd please refer to the available manual on:

How to compile termnetd

Download the source files from this link:

and save in the apps directory and type:

../sdkroot/apps# tar xvzf termnetd_3-3.tgz
../sdkroot/apps# cd termnetd
../sdkroot/apps/termnetd# make cris-axis-linux-gnu
../sdkroot/apps/termnetd# make

You will obtain the executable file: termnetd


  • Ready to use executabe file (need an image with glibc library) termnetd
  • An example of termnetd.conf file: termnetd.conf

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